Tag Archives: Dr. Jeff Masters

Dr. Jeff Masters on Climate Extremes

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In 2011, a series of violent severe storms swept across the Plains and Southeast U.S., bringing an astonishing six billion-dollar disasters in a three-month period. The epic tornado onslaught killed 552 people, caused $25 billion in damage, and brought three of the five largest tornado outbreaks since record keeping began in 1950. In May 2011, the Joplin, Missouri tornado did $3 billion in damage–the most expensive tornado in world history–and killed 158 people, the largest death toll from a U.S. tornado since 1947. An astounding 1050 EF-1 and stronger tornadoes ripped though the U.S. for the one-year period ending that month. This was the greatest 12-month total for these stronger tornadoes in the historical record, and an event so rare that we might expect it to occur only once every 62,500 years. Fast forward now to May 2012 – April 2013. Top-ten coldest temperatures on record across the Midwest during March and April of 2013, coming after a summer of near-record heat and drought in 2012, brought about a remarkable reversal in our tornado tally–the lowest 12-month total of EF-1 and stronger tornadoes on record–just 197. This was an event so rare we might expect it to occur only once every 3,000 – 4,000 years. And now, in May 2013, after another shattering EF-5 tornado in Moore, Oklahoma, residents of the Midwest must be wondering, are we back to the 2011 pattern? Which of these extremes is climate change most likely to bring about? Is climate change already affecting these storms? These are hugely important questions, but ones we don’t have good answers for. Climate change is significantly impacting the environment that storms form in, giving them more moisture and energy to draw upon, and altering large-scale jet stream patterns. We should expect that this will potentially cause major changes in tornadoes and severe thunderstorms. Unfortunately, tornadoes and severe thunderstorms are the extreme weather phenomena we have the least understanding on with respect to climate change. We don’t have a good enough database to determine how tornadoes may have changed in recent decades, and our computer models are currently not able to tell us if tornadoes are more likely to increase or decrease in a future warmer climate.

Video 1. Remarkable video of the tornado that hit Tuscaloosa, Alabama on April 27, 2011, part of the largest and most expensive tornado outbreak in U.S. history–the $10.2 billion dollar Southeast U.S. Super Outbreak of April 25 – 28, 2011. With damage estimated at $2.2 billion, the Tuscaloosa tornado was the 2nd most expensive tornado in world history, behind the 2011 Joplin, Missouri tornado. Fast forward to minute four to see the worst of the storm.


Figure 1. Will climate change increase the incidence of these sorts of frightening radar images? Multiple hook echoes from at least ten supercell thunderstorms cover Mississippi, Alabama, and Tennessee in this radar image taken during the height of the April 27, 2011 Super Outbreak, the largest and most expensive tornado outbreak in U.S. history. A multi-hour animation is available here.

Changes in past tornado activity difficult to assess due to a poor database
It’s tough to tell if tornadoes may have changed due to a changing climate, since the tornado database is of poor quality for climate research. We cannot measure the wind speeds of a tornado directly, except in very rare cases when researchers happen to be present with sophisticated research equipment. A tornado has to run over a building and cause damage before an intensity rating can be assigned. The National Weather Service did not begin doing systematic tornado damage surveys until 1976, so all tornadoes from 1950 – 1975 were assigned a rating on the Fujita Scale (F-scale) based on old newspaper accounts and photos. An improved Enhanced Fujita (EF) scale to rate tornadoes was adopted in 2007. The transition to the new EF scale still allows valid comparisons of tornadoes rated, for example, EF-5 on the new scale and F5 on the old scale, but does create some problems for tornado researchers studying long-term changes in tornado activity. More problematic is the major changes in the Fujita-scale rating process that occurred in the mid-1970s (when damage surveys began), and again in 2001, when scientists began rating tornadoes lower because of engineering concerns and unintended consequences of National Weather Service policy changes. According to Brooks (2013), “Tornadoes in the early part of the official National Weather Service record (1950 – approximately 1975) are rated with higher ratings than the 1975 – 2000 period, which, in turn, had higher ratings than 2001 – 2007.” All of these factors cause considerable uncertainty when attempting to assess if tornadoes are changing over time. At a first glance, it appears that tornado frequency has increased in recent decades (Figure 2). However, this increase may be entirely caused by factors unrelated to climate change:

1) Population growth has resulted in more tornadoes being reported. Heightened awareness of tornadoes has also helped; the 1996 Hollywood blockbuster movie Twister “played no small part” in a boom in reported tornadoes, according to tornado scientist Dr. Nikolai Dotzek.

2) Advances in weather radar, particularly the deployment of about 100 Doppler radars across the U.S. in the mid-1990s, has resulted in a much higher tornado detection rate.

3) Tornado damage surveys have grown more sophisticated over the years. For example, we now commonly classify multiple tornadoes along a damage path that might have been attributed to just one twister in the past.


Figure 2. The total number of U.S. tornadoes since 1950 has shown a substantial increase. Image credit: NOAA/NCDC.


Figure 3. The number of EF-0 (blue line) and EF-1 and stronger tornadoes (maroon squares) reported in the U.S. since 1950. The rise in number of tornadoes in recent decades is seen to be primarily in the weakest EF-0 twisters. As far as we can tell (which isn’t very well, since the historical database of tornadoes is of poor quality), there is not a decades-long increasing trend in the numbers of tornadoes stronger than EF-0. Since these stronger tornadoes are the ones most likely to be detected, this implies that climate change, as yet, is not having a noticeable impact on U.S. tornadoes. Image credit: Kunkel, Kenneth E., et al., 2013, “Monitoring and Understanding Trends in Extreme Storms: State of Knowledge,” Bull. Amer. Meteor. Soc., 94, 499–514, doi: http://dx.doi.org/10.1175/BAMS-D-11-00262.1


Figure 4. Insured damage losses in the U.S. due to thunderstorms and tornadoes, as compiled by Munich Re. Damages have increased sharply in the past decade, but not enough to say that an increase in tornadoes and severe thunderstorms may be to blame.

Stronger tornadoes do not appear to be increasing
Tornadoes stronger than EF-0 on the Enhanced Fujita Scale (or F0 on the pre-2007 Fujita Scale) are more likely to get counted, since they tend to cause significant damage along a long track. Thus, the climatology of these tornadoes may offer a clue as to how climate change may be affecting severe weather. If the number of strong tornadoes has actually remained constant over the years, we should expect to see some increase in these twisters over the decades, since more buildings have been erected in the paths of tornadoes. However, if we look at the statistics of U.S. tornadoes stronger than EF-0 or F-0 since 1950, there does not appear to be any increase in their number (Figure 3.) Damages from thunderstorms and tornadoes have shown a significant increase in recent decades (Figure 4), but looking at damages is a poor way to determine if climate change is affecting severe weather, since there are so many human factors involved. A study in Environmental Hazards (Simmons et al., 2012) found no increase in tornado damages from 1950 – 2011, after normalizing the data for increases in wealth and property. Also, Bouwer (BAMS, 2010) reviewed 22 disaster loss studies world-wide, published 2001 – 2010; in all 22 studies, increases in wealth and population were the “most important drivers for growing disaster losses.” His conclusion: human-caused climate change “so far has not had a significant impact on losses from natural disasters.” Studies that normalize disaster data are prone to error, as revealed by a 2012 study looking at storm surge heights and damages. Given the high amount of uncertainty in the tornado and tornado damage databases, the conclusion of the “official word” on climate science, the 2007 United Nations IPCC report, pretty much sums things up: “There is insufficient evidence to determine whether trends exist in small scale phenomena such as tornadoes, hail, lighting, and dust storms.” Until a technology is developed that can reliably detect all tornadoes, there is no hope of determining how tornadoes might be changing in response to a changing climate. According to Doswell (2007): “I see no near-term solution to the problem of detecting detailed spatial and temporal trends in the occurrence of tornadoes by using the observed data in its current form or in any form likely to evolve in the near future.”


Figure 5. Wind shear from the surface to 6 km altitude in May on days with days with higher risk conditions for severe weather (upper-10% instability and wind shear) over the South Central U.S. has shown no significant change between 1950 – 2010. Image credit: Brooks, 2013, “The spatial distribution of severe thunderstorm and tornado environments from global reanalysis data”, Atmospheric Research Volumes 67-68, July-September 2003, Pages 73-94.


Figure 6. Six-hourly periods per year with environments supportive of significant severe thunderstorms in the U.S. east of the Rocky Mountains. The line is a local least-squares regression fit to the series, and shows no significant change in environments supportive of significant severe thunderstorms in recent decades. Image credit: Brooks, H.E., and N. Dotek, 2008, “The spatial distribution of severe convective storms and an analysis of their secular changes”, Climate Extremes and Society

How are the background conditions that spawn tornadoes changing?
An alternate technique to study how climate change may be affecting tornadoes is look at how the large-scale environmental conditions favorable for tornado formation have changed through time. Moisture, instability, lift, and wind shear are needed for tornadic thunderstorms to form. The exact mix required varies considerably depending upon the situation, and is not well understood. However, Brooks (2003) attempted to develop a climatology of weather conditions conducive for tornado formation by looking at atmospheric instability (as measured by the Convective Available Potential Energy, or CAPE), and the amount of wind shear between the surface and 6 km altitude. High values of CAPE and surface to 6 km wind shear are conducive to formation of tornadic thunderstorms. The regions they analyzed with high CAPE and high shear for the period 1997-1999 did correspond pretty well with regions where significant (F2 and stronger) tornadoes occurred. Riemann-Campe et al. (2009) found that globally, CAPE increased significantly between 1958 – 2001. However, little change in CAPE was found over the Central and Eastern U.S. during spring and summer during the most recent period they studied, 1979 – 2001. Brooks (2013) found no significant trends in wind shear over the U.S. from 1950 – 2010 (Figure 5.) A preliminary report issued by NOAA’s Climate Attribution Rapid Response Team in July 2011 found no trends in CAPE or wind shear over the lower Mississippi Valley over the past 30 years.


Figure 7. Change in the number of days per year with a high severe thunderstorm potential as predicted by the climate model (A2 scenario) of Trapp et al. 2007, due to predicted changes in wind shear and Convective Available Potential Energy (CAPE). Most of the U.S. east of the Rocky Mountains is expected to see 1 – 2 additional days per year with the potential for severe thunderstorms. The greatest increase in potential severe thunderstorm days (three) is expected along the North and South Carolina coast. Image credit: NASA.

How will tornadoes and severe thunderstorms change in the future?
Using a high-resolution regional climate model (25 km grid size) zoomed in on the U.S., Trapp et al. (2007) and Trapp et al. (2009) found that the decrease in 0-6 km wind shear in the late 21st century would more than be made up for by an increase in instability (CAPE). Their model predicted an increase in the number of days with high severe storm potential for most of the U.S. by the end of the 21st century, particularly for locations east of the Rocky Mountains (Figure 7.) Brooks (2013) also found that severe thunderstorms would likely increase over the U.S. by the end of the century, but theorized that the severe thunderstorms of the future might have a higher proportion causing straight-line wind damage, and slightly lower proportion spawning tornadoes and large hail. For example, a plausible typical future severe thunderstorm day many decades from now might have wind shear lower by 1 m/s, but a 2 m/s increase in maximum thunderstorm updraft speed. This might cause a 5% reduction in the fraction of severe thunderstorms spawning tornadoes, but a 5% increase in the fraction of severe thunderstorms with damaging straight-line winds. He comments: “However, if the number of overall favorable environments increases, there may be little change, if any, in the number of tornadoes or hailstorms in the US, even if the relative fraction decreases. The signals in the climate models and our physical understanding of the details of storm-scale processes are sufficiently limited to make it extremely hazardous to make predictions of large changes or to focus on small regions. Projected changes would be well within error estimates.”


Figure 8. From 1995 (the first year we have wind death data) through 2012, deaths from high winds associated with severe thunderstorms accounted for 8% of all U.S. weather fatalities, while tornadoes accounted for 13%. Data from NOAA.

Severe thunderstorms are capable of killing more people than tornadoes
If the future climate does cause fewer tornadoes but more severe thunderstorms, this may not end up reducing the overall deaths and damages from these dangerous weather phenomena. In 2012, the warmest year in U.S. history, the death toll from severe thunderstorms hit 104–higher than the 70 people killed by tornadoes that year. Severe thunderstorms occur preferentially during the hottest months of the year, June July and August, and are energized by record heat. For example, wunderground weather historian Christopher C. Burt called the number of all-time heat records set on June 29, 2012 “especially extraordinary,” and on that day, an organized thunderstorm complex called a derecho swept across a 700-mile swath of the Ohio Valley and Mid-Atlantic, killing thirteen people and causing more than $1 billion in damage. The amount of energy available to the derecho was extreme, due to the record heat. The derecho knocked out power to 4 million people for up to a week, in areas where the record heat wave was causing high heat stress. Heat claimed 34 lives in areas without power in the week following the derecho. Excessive heat has been the number one cause of weather-related deaths in the U.S since 1995, killing more than twice as many people as tornadoes have. Climate models are not detailed enough to predict how organized severe thunderstorm events such as derechos might change in a future warmer climate. But a warmer atmosphere certainly contributed to the intensity of the 2012 derecho, and we will be seeing a lot more summers like 2012 in coming decades. A future with sharply increased damages and deaths due to more intense severe thunderstorms and derechos is one nasty climate change surprise that may lurk ahead.


Figure 9. Lightning over Tucson, Arizona on August 14, 2012. A modeling study by Del Genio et al.(2007) predicts that lighting will increase by 6% by the end of the century, potentially leading to an increase in lightning-triggered wildfires. Image credit: wunderphotographer ChandlerMike.

Lightning may increase in a warmer climate
Del Genio et al.(2007) used a climate model with doubled CO2 to show that a warming climate would make the atmosphere more unstable (higher CAPE) and thus prone to more severe weather. However, decreases in wind shear offset this effect, resulting in little change in the amount of severe weather in the Central and Eastern U.S. late this century. However, they found that there would likely be an increase in the very strongest thunderstorms. The speed of updrafts in thunderstorms over land increased by about 1 m/s in their simulation, since upward moving air needed to travel 50 – 70 mb higher to reach the freezing level, resulting in stronger thunderstorms. In the Western U.S., the simulation showed that drying led lead to fewer thunderstorms overall, but the strongest thunderstorms increased in number by 26%, leading to a 6% increase in the total amount of lighting hitting the ground each year. If these results are correct, we might expect more lightning-caused fires in the Western U.S. late this century, due to increased drying and more lightning. Only 12% of U.S. wildfires are ignited by natural causes, but these account for 52% of the acres burned (U.S. Fire Administration, 2000). So, even a small change in lightning flash rate has important consequences. Lightning is also a major killer, as an average of 52 people per year were killed by lightning strikes over the 30-year period ending in 2012, accounting for 6% of all U.S. weather-related fatalities.

Summary
We currently do not know how tornadoes and severe thunderstorms may be changing due to climate change, nor is there hope that we will be able to do so in the foreseeable future. It does not appear that there has been an increase in U.S. tornadoes stronger than EF-0 in recent decades, but climate change appears to be causing more extreme years–both high and low–of late. Tornado researcher Dr. Harold Brooks of the National Severe Storms Laboratory in Norman, Oklahoma said in a 2013 interview on Andrew Revkin’s New York Times dotearth blog: “there’s evidence to suggest that we have seen an increase in the variability of tornado occurrence in the U.S.” Preliminary research using climate models suggests that we may see an increase in the number of severe thunderstorms capable of producing tornadoes over the U.S. late this century, but these thunderstorms will be more likely to produce damaging straight-line winds, and less likely to produce tornadoes and large hail. This will not necessarily result in a reduction in deaths and damages, though, since severe thunderstorms can be just as dangerous and deadly as tornadoes–especially when they knock out power to areas suffering high-stress heat waves. Research into climate change impacts on severe weather is just beginning, and much more study is needed.

from:    http://www.wunderground.com/blog/JeffMasters/show.html

Jeff Masters on Tornadoes & Typhoons

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After going twelve months with a record-low tornado death toll of just seven people, last night we received a jolting reminder that tornadoes typically kill a lot more people than that in the U.S. A deadly tornado swept through Granbury, Texas near 8 pm CDT, killing six and injuring up to 100. The weather system that spawned the Granby tornado also unleashed a mile-wide twister that hit Cleburne, about 25 miles southeast of Granbury. Damage was heavy in Cleburne and a state of emergency declared, but only seven minor injuries were reported. A third tornado hit the small town of Millsap, about 40 miles west of Fort Worth, causing roof damage a destroying a barn, but caused no injuries. Preliminary figures indicate that a total ten tornadoes touched down in Texas last night, and NWS damage survey teams are out today to determine the exact total and how strong they were. The National Weather Service out of Fort Worth has issued a preliminary rating of EF-4 to the Granbury tornado, making it the first tornado stronger than EF-0 reported in May 2013. The storms also dumped softball-sized hail up to 4″ in diameter in Mineral Wells, TX.

Video 1. The Granbury, Texas tornado of May 15, 2013.

Thursday’s tornado was the deadliest U.S. tornado in over a year. The last time six people died in a U.S. tornado was on April 14, 2012, during an EF-3 tornado that hit Woodward, Oklahoma. The last Texas tornado that was deadlier occurred on April 24, 2007 in Maverick County, when an EF-3 tornado hit Eagle Pass, Texas, killing seven. Texas has had one other tornado death in 2013, from a twister that hit on February 21, 2013, in Sabine County. The region of Texas hit by last night’s tornadoes has few basements, which may have contributed to the death toll. According to underground member Seattleite, “In this part of Texas basements are very uncommon. The reason is due to the soil, it is basically clay. It contracts and expands with temperature and moisture levels on the order of a foot or more in a typical year. The pressure from this can cause basement walls to cave. They can be built, but it costs at least an extra $20,000+, as they surround the basement with a sand-like barrier to handle the changes in the ground.”


Figure 1. Softball, anyone? One of the 4″ hailstones that fell near Mineral Wells, Texas on May 15, 2013. Image from Patrick Vondra via Twitter.

Is the 2012 – 2013 tornado drought over?
Thanks to the cold spring in the Midwest during 2013, and the 2012 Midwest drought, the 197 EF-1 and stronger tornadoes that occurred during May 2012 – April 2012 was an all-time minimum for any twelve-month period since at least 1954, wrote tornado researcher Harold Brooks at the U.S. Severe Weather Blog (previous minimum: 247 tornadoes from June 1991-May 1992.) The death toll of just seven was also a record low for any twelve-month period since 1950. Amazingly, this tornado drought occurred less than two years after the record maximum: 1050 EF-1 and stronger tornadoes from June 2010 – May 2011. The extraordinary contrast underscores the crazy fluctuations we’ve seen in Northern Hemisphere jet stream patterns during the past three years. Call it “Weather Whiplash” of the tornado variety. A blog post by meteorologist Patrick Marsh of NOAA’s Storm Prediction Center argues that the record 12-month tornado maximum of 1050 EF-1 and stronger tornadoes from June 2010 – May 2011 was a 1-in-62,500 year event. The record 12-month minimum of 197 EF-1 and stronger tornadoes that occurred from May 2012 – April 2013 was a 1-in-3000 to 1-in-4000 year event. In Marsh’s words: “Anyway you look at it, the recent tornado “surplus” and the current tornado “drought” is extremely rare. The fact that we had both of them in the span of a few years is even more so!”

Our tornado drought may be at its end, as the latest forecasts from NOAA’s Storm Prediction Center call for an active severe weather pattern Saturday – Monday. The current forecast calls for just a “Slight Risk” on Saturday over the Northern Plains, but the threat will grow on Sunday and Monday as a powerful spring weather system gathers strength over the center of the country.

Saturday’s main threat areas: SD to NE, and northern KS
Sunday : IA, parts of MO/KS, to central/eastern OK
Monday : IL/MO to OK/TX border


Figure 2. MODIS image of Tropical Cyclone Mahasen taken at 06:50 UTC Thursday May 16, 2013. Mahasen made landfall about two hour prior to this image as a tropical storm with 50 mph winds. Image credit: NASA.

Tropical Storm Mahasen hits Bangladesh
Tropical Storm Mahasen hit the Bangladesh coast near 08 UTC Thursday, May 16 near a place called Feni north of Chittagong. Mahasen was a tropical storm with top winds of 50 mph at landfall. Satellite observations suggest that the storm was becoming much more organized just before landfall, and it is fortunate that the storm ran out of time to intensify when it did. Mahasen likely brought a storm surge of up to a meter (3.3 feet) to the coast of Bangladesh, but it is the storm’s rains that are causing the main problems. Satellite rainfall forecasts made at landfall show that Mahasen could dump up to 20 inches of rain along a swath through Bangladesh and into Northeastern India. These rains will be capable of causing destructive flooding, and ten deaths have already been reported in Bangladesh from the storm. At least eight people have been killed in Sri Lanka due to landslides triggered by Mahasen’s heavy rains, and a boat carrying refugees capsized on Monday, killing eight and leaving 50 missing.

First tropical storm of the year, Alvin, forms in the Eastern Pacific
The official start of hurricane season in the Eastern Pacific is Wednesday, May 15, and Mother Nature emphatically agreed, bringing us the first named storm of the year, Tropical Storm Alvin. With wind shear a moderate 10 – 20 knots and the storm currently struggling to hold itself together, it currently appears unlikely that we will see a Hurricane Alvin. The storm is moving west-northwest into the Central Pacific, and is not a threat to any land areas.

from:    http://www.wunderground.com/blog/JeffMasters/show.html

Dr. Jeff Masters on May Snowstorm

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A rare and historic May snowstorm continues to pelt Iowa, Minnesota, and Wisconsin with snowfall amounts unprecedented in the historical record for the month of May. Winter Storm Achilles has brought 15.5″ of snow to Owatonna, Minnesota, about 50 miles south of Minneapolis. This is (unofficially) the largest May snowstorm in state history, surpassing the 3-day total of a 15″ snowstorm at Sandy Lake Dam/Libby. The 14.7″ of snow that has fallen at Baldwin, Wisconsin is just shy of Wisconsin’s May state record snowfall of 15.4″. Minneapolis just missed getting heavy snow, as bands of heavy snow with thunder and snowfall rates over one inch per hour set up over Northeast Iowa and Southeast Minnesota early this morning. There are multiple reports of tree damage across Red Wing, Owatonna, and other locations in eastern Minnesota and western Wisconsin, with power outages in the thousands across the Red Wing area. I-35 is closed in both directions just north of Owatonna due to snow cover and downed power lines.

Here are the latest peak snowfall totals by state as of early Thursday morning:
• Buckhorn Mtn., Colo.:  28.2″
• Near Buford, Wyo.:  20″
• Near Harrisburg, Neb.:  6.1″
• Ringsted, Iowa:  6.5″
• Owatonna, Minn.:  15.5″
• Beresford, S.D.:  6″
• Baldwin, Wisc.:  14.7″


Figure 1. Not yet! “Looks like I got the deck furniture out a little early,” writes wunderphotographer MikePic in his caption for this photo taken on May 1, 2013 in Wheat Ridge, Colorado.


Figure 2. Observed snowfall amounts in inches from the May 1 – 2, 2013 snowstorm as of 9am EDT May 2. Image credit: NWS Minneapolis.

A historic May snowstorm for many locations
Rochester, Minnesota has received 7″ of snow, smashing their all-time May snowstorm record of 2″, set on May 4 – 5, 1944.

Over 3″ of snow has fallen in Omaha, Nebraska, breaking their all-time May snowstorm record of 2″ on May 9, 1945.

It was the first one-inch-plus May snowfall anywhere in the state of Iowa since 1967. A storm-high 6.5″ fell in Iowa at Ringsted.

The 1.5″ of snow that fell on Sioux Falls, South Dakota Wednesday was that city’s first May snowfall since 1976, the first May snowfall of greater than one inch since 1944, and the 3rd highest May snowfall on record.

Topeka, Kansas, Kansas City, Missouri, and Des Moines, Iowa are all expected to get an inch or more of snow on Thursday through Friday. This would be only the second May snowstorm in recorded history for those cities. Their only other May snowstorm occurred on May 3, 1907 (3.2″ at Topeka, 1.7″ at Kansas City, and 1.2″ at Des Moines.)

from:    http://www.wunderground.com/blog/JeffMasters/show.html

D. Jeff Masters on February Weather Records

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February 2013 the globe’s 9th warmest February on record
Published: 2:31 PM GMT on March 15, 2013

February 2013 was the globe’s 9th warmest February since records began in 1880, said National Oceanic and Atmospheric Administration’s National Climatic Data Center (NCDC) on Thursday. February 2013 global land temperatures were the 11th warmest on record, and global ocean temperatures were the 8th warmest on record. February 2013 was the 336th consecutive month with global temperatures warmer than the 20th century average and the 37th straight warmer-than-average February. The last time Earth had a below-average February global temperature was in 1976, and the last below-average month of any kind was December 1984. Global satellite-measured temperatures in February 2013 for the lowest 8 km of the atmosphere were 10th or 8th warmest in the 35-year record, according to Remote Sensing Systems and the University of Alabama Huntsville (UAH), respectively. The Northern Hemisphere snow cover extent during February 2013 was the 16th largest in the 47-year period of record. Wunderground’s weather historian, Christopher C. Burt, has a comprehensive post on the notable weather events of February 2013 in his February 2013 Global Weather Extremes Summary. Costly weather disasters were relatively rare in February, according to AON Benfield. The most expensive weather-related disasters in February 2013 were:

1) Drought in Central and Eastern China, 1/1 – 2/28, $541 million
2) Winter storm in Eastern China, 2/18 – 2/21, $124 million
3) Winter Storm Nemo, Northeast U.S., 2/8 – 2/9. $100+ million
4) Hattiesburg, MS tornado and associated storm damage, 2/9 – 2/11, $100+ million

The deadliest February weather disaster was Tropical Cyclone Haruna, which hit Madagascar at 00 UTC Friday, February 22, as a Category 2 storm with 105 mph winds, killing 26.


Figure 1. Departure of temperature from average for February 2013, the 9th warmest February for the globe since record keeping began in 1880. Colder than average conditions occurred in the Western U.S., western Europe, and northern Russia. No land areas in the Southern Hemisphere were cooler than average, and record warm conditions were experienced in parts of Indonesia and northern Australia. Image credit: National Climatic Data Center (NCDC) .


Figure 2. The deadliest weather disaster of February 2013 was Tropical Cyclone Haruna, which hit Madagascar at 00 UTC Friday, February 22, as a Category 2 storm with 105 mph winds, killing 26. In this image, Haruna is over Madagascar at 11:05 UTC February 22, 2013, and was a Category 1 storm with 90 mph winds. Image credit: NASA.


Figure 3. The most expensive weather disaster of February 2013 was the on-going drought in Central and Eastern China, which has cost $541 million since the beginning of 2013. Image credit: Beijing Climate Center.

Neutral El Niño conditions continue in the equatorial Pacific
For the 11th month in row, neutral El Niño conditions existed in the equatorial Pacific during February 2013. NOAA’s Climate Prediction Center (CPC) expects neutral El Niño conditions to last through spring. Temperatures in the equatorial Eastern Pacific need to be 0.5°C below average or cooler for three consecutive for a La Niña episode to be declared; sea surface temperatures were 0.1°C below average as of March 11, and have ranged from 0.1 – 0.6°C below average during 2013.

Arctic sea ice falls to 7th lowest February extent on record
Arctic sea ice extent during February reached its seventh lowest extent in the 35-year satellite record, according to the National Snow and Ice Data Center (NSIDC). This was the 11th consecutive February and 141st consecutive month with below-average Arctic sea ice extent. The last ten years (2004 to 2013) have seen the ten lowest February extents in the satellite record. Arctic sea ice is nearing its winter maximum and will soon begin to melt.

from:    http://www.wunderground.com/blog/JeffMasters/article.html

Dr. Jeff Masters on The Drought

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Late February storms put only a slight dent in U.S. drought
Published: 4:14 PM GMT on February 28, 2013
Abundant moisture from heavy rains and snows that fell during two major Midwest storms in late February put only a slight dent in the great Midwest drought of 2012 – 2013. According to the February 28, 2013 Drought Monitor, the percentage area of the contiguous U.S. suffering moderate or greater drought shrank from 56% to 54%, and the area in the worst category of drought–exceptional drought–fell from 6.7% to 5.4% over the past week. These are the largest 1-week improvements in these drought categories that we’ve seen for 9 months and 15 months, respectively. The improvements were most noteworthy in Oklahoma, the Texas Panhandle, and the Southeast U.S., where drought improved by a full category (using the level 1 to 4 categories of the Palmer Drought Severity Index.) However, the dry pattern that has been dominant over the U.S. for most of the past year will re-assert itself during the coming ten days, and most of the drought region will receive less than 0.5″ of precipitation through March 9. There exists the possibility of a significant Midwest storm on March 10, according to recent runs of the GFS and ECMWF computer models, but it is too early to assess if this storm may be able to provide significant drought relief. In general, droughts are more likely in the Midwest U.S. when warmer than average ocean temperatures prevail in the tropical Atlantic, with cooler than average ocean temperatures in the tropical Eastern Pacific (La Niña-like conditions.) This is what we had in during most of 2012, and continue to have in 2013. Equatorial East Pacific ocean temperatures are currently 0.5°C below average. This is similar to the ocean temperatures seen in the spring of 2012, just before the Great Drought of 2012 began. Most of the U.S. drought region needs 3 – 9″ of precipitation to pull out of drought. Unless the Midwest receives a top-ten percent wettest spring on record, drought is going to be a huge concern as we enter summer.


Figure 1. Drought conditions as of February 28, 2013 showed that drought still gripped a majority of the U.S. Image credit: U.S. Drought Monitor.


Figure 2. Predicted 7-day precipitation for the period ending Thursday, March 7. Less than 10% of the U.S. drought regions are predicted to receive as much as 0.5″ of precipitation (dark green color.) Image credit: NOAA/HPC.

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/article.html

And Nemo Arrives in the Northeast

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Snows begin in Northeast U.S. as historic Nor’easter strengthens
Published: 3:17 PM GMT on February 08, 2013

Snow has begun falling from New York City to Massachusetts, where blizzard warnings are flying in anticipation of the arrival of one of the most severe and dangerous Nor’easters in U.S. history. The great storm, dubbed “Nemo”, has just emerged into the waters off the coast of Virginia, and is predicted to “bomb” to a central pressure of 975 – 980 mb by Saturday afternoon. Cold, Arctic air spilling southwards behind a strong 1038 mb high over Canada will collide with warm, moist air over the Atlantic, where ocean temperatures are unusually warm–about 5°F warmer than average over a large swath from New Jersey to Nantucket, Massachusetts. The contrast between the cold and warm air will help intensify the storm, and the unusually warm waters will pump large quantities of moisture into the air, which will be capable of feeding record-breaking snows over New England. The latest NWS forecast for Boston calls for 22 – 30″ of snow by Saturday morning, with additional snows though Saturday afternoon. Since Boston’s all-time heaviest snow storm is 27.5″ (February 17-18, 2003), Winter Storm Nemo has a chance of exceeding that. According to NWS, here are the top snowstorms since 1936 for Logan Airport:

1. February 17-18, 2003 27.5″
2. February 6-7, 1978 27.1″
3. February 24-27, 1969 26.3″
4. March 31-April 1, 1997 25.4″
5. January 22-24, 1945 22.8″
6. January 22-23, 2005 22.5″
7. January 20-21, 1978 21.4″
8. March 3-5, 1960 19.8″
9. February 16-17, 1958 19.4″
10. February 8-10, 1994 18.7″
11. January 7-8, 1996 18.2″
11. December 20-22, 1975 18.2″
11. December 26-27, 2010 18.2″

The weight of all that heavy snow on rooftops will create the danger of roof collapses. In addition to the heavy snow, the storm will bring coastal wind gusts over hurricane force, and moderate to major coastal flooding. During the peak of the storm, Friday night into Saturday morning, snowfall rates of 2 – 3″ per hour can be expected. These intense bursts of snow may be accompanied by lightning and thunder. The cites of Hartford, Providence, and Portland are all likely to get more than a foot of snow, and two feet of snow will probably fall along a swath from South Central Connecticut to Southwest Maine, with isolated amounts of 3′. Ferocious sustained winds near 50 mph will occur at the coast, with wind gusts in excess of hurricane force–74 mph. The combination of heavy snow and high winds will make travel extremely dangerous or impossible, with near-zero visibility in white-out conditions. The snow and high winds are likely to cause many power outages.


Figure 1. Predicted snowfall for Winter Storm Nemo from Friday’s 00Z run of the European (ECMWF) model. The highest snowfall amounts (> 24″) are predicted for Long Island, Southern Connecticut, and Eastern Massachusetts, including Boston. This forecast assumes that the ratio between liquid water equivalent and snow depth will be 10:1. In some areas away from the coast, this ratio may be closer to 15:1, leading to snow amounts near 36″.


Figure 2. Predicted wind speeds in knots at 7 am EST Saturday, February 9, 2013, from the 00Z February 8, 2013 run of the European (ECMWF) model. The model is predicting sustained winds of 50 knots (57.5 mph) will be just offshore of Cape Cod and Nantucket Island, Massachusetts. Multiply by 1.15 to convert knots to mph.

Serious coastal flooding expected in Massachusetts
The high winds from the storm will drive a damaging storm surge of 2 – 4′ along the coast of Eastern Massachusetts Friday night and Saturday morning. High tide Friday night will occur between 9:30 – 10 pm EST, and minor to moderate coastal flooding is expected along east and north-facing shores, when the storm surge of 2 – 3′ rides in on top of the tide. Battering waves of 8 – 17′ will hit the coast south of Boston in Cape Cod Bay, causing severe beach erosion. Of greater concern is the flooding that will occur during the Saturday morning high tide cycle, as that is the time of the new moon, which will bring the highest tide of the month. The ocean’s height near Boston varies naturally by about ten feet between low tide and high tide, so it matters greatly when the storm surge arrives, relative to the tidal cycle. Thus we speak of the “storm tide”–how high the water gets above the high tide mark, due to the combination of the storm surge and the tide. During Hurricane Sandy, on October 29, 2012, a potentially very damaging storm surge of 4.57′ hit Boston, but arrived near low tide, so the water level during the peak surge did not rise above the normal high tide mark. Fortunately, it appears that the peak storm surge from Nemo will arrive at the time of low tide early Saturday morning, and the surge will have fallen about a foot by the time the high tide arrives near 10 am EST Saturday. As of 9am EST on February 8, 2013, the latest storm surge forecast from the GFS model was calling for a storm tide of about 3.4′ above high tide (MHHW, Mean Higher High Water) in Boston on Saturday morning. This would cause minor to moderate flooding in the city, and would be approximately the 10th highest water level on record. The official top 5 storm tides since 1921 at the Boston tide gauge, relative to MHHW, are:

1. 4.82′ – February 7, 1978 (Blizzard of 1978)
2. 3.92′ – January 2, 1987
3. 3.86′ – October 30, 1991 (Perfect Storm)
4. 3.76′ – January 28, 1979
5. 3.75′ – December 12, 1992

More serious flooding is expected in Cape Cod Bay to the southeast of Boston, where the northeast winds from the storm will pile up a higher storm surge. A storm surge of 3 – 4′ is predicted from Scituate to Sandwich Harbor Saturday morning. The surge will be accompanied by battering waves 18 – 26′ feet high, and major flooding and significant coastal erosion is expected. Major coastal flooding is also expected on the east end of Nantucket Island.

Severe beach erosion is also expected along the north and northeast facing shores of Long Island, NY, where a storm surge of 3 – 5′ will combine with 4 – 8′ breaking waves. Minor to moderate coastal flooding is expected along western Long Island Sound. New York City is expecting a 2 – 4′ storm surge, which will cause mostly minor flooding, with a few areas of moderate flooding.


Figure 3. Coastal flooding hazards during the high tide cycle on Saturday morning, February 9, 2013, as predicted at 5 am EDT Friday, February 8, 2013, by the NWS Boston.

from:    http://www.wunderground.com/blog/JeffMasters/article.html

Dr. Jeff Masters on The Week’s Wild Weather

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Wild weather week ends; Mississippi River rises out of danger zone
Published: 2:44 PM GMT on February 01, 2013
One of the most unusual weeks of January weather in U.S. history has drawn to a close, and residents of the Southeast are cleaning up after a ferocious 2-day outbreak of severe weather. NWS damage surveys have found that at least 42 tornadoes touched down on January 29 – 30, making it the 3rd largest January tornado outbreak since records began in 1950. Here are the largest January tornado outbreaks since 1950:129 1/21 – 1/22 1999
50 1/7 – 1/8 2008
42 1/29 – 1/30 2013
40 1/9 1/10 1975

As wunderground’s Angela Fritz wrote in her blog today, the powerful tornado that ripped through Adairsville, Georgia, northwest of Atlanta, at 11:19 am EST Thursday morning, killing one person, has been rated a high-end EF-3 with 160 mph winds. At least seven other tornadoes in the outbreak were EF-2s. Damaging winds reports for the 2-day period numbered 597, the highest 2-day January total since NOAA’s Storm Prediction Center (SPC) began tabulating these in 2000. The severe weather outbreak was fueled an air mass that set many all-time January records for warmth and moisture, as detailed by our weather historian, Christopher C. Burt, in his latest post, A Wild Ride Weather-wise for the Eastern Half of the U.S. the past Four Days.


Figure 1. Damage to the Daiki Corporation factory in Adairsville, GA, after the January 30, 2013 EF-3 tornado. Image credit: Dr. Greg Forbes, TWC.


Figure 2. Severe weather reports for the month of January; 597 reports of damaging winds were recorded January 29 – 30. Image credit: NOAA/SPC.

Mississippi River rising
This week’s storm brought widespread rains of 1 – 2″ to Missouri and Illinois, along the drainage basin of the stretch of the Mississippi River that was so low as to threaten to stop barge traffic. Happily, the rains have caused the river to rise by more than seven feet over the past week, along the stretch from St. Louis to Thebes, Illinois. Thanks to this much-needed bump in river levels, plus the future run-off that will occur from the snows that have accumulated in Minnesota, Wisconsin, and Iowa, I expect no potential low water closures of the Mississippi until June at the earliest. According to today’s newly-released Drought Monitor, though, the area of the contiguous U.S. in moderate or greater drought remained unchanged at 58% this week. It will be dry across the core of the drought region for at least the next week; the GFS model is predicting that the next chance of significant precipitation for the drought region will be Saturday, February 9. Don’t bet on this happening, though, since the model has been inconsistent with its handling of the storm. The drought has killed hundreds of thousands of trees across the Midwest, and many more will succumb during the next few years. According to Brian Fuchs, a climatologist with the National Drought Mitigation Center, drought was present in at least isolated spots in all 50 states of the U.S. for the first time in history during 2012.


Figure 3. The water level in the Mississippi River at St. Louis was at -4′ early this week, just above the all-time record low of -6.2′ set in 1940. However, rains from this week’s storm have raised water levels by seven feet. Image credit: NOAA/HPC.


Figure 4. The liquid equivalent of melting all the snow on the ground present on February 1, 2013. Widespread amounts of water equivalent to 0.39″ – 2″ of rain are present over Minnesota, Wisconsin, and Iowa, which is near average for this time of year. When this snow melts, it will raise the level of the Mississippi River and aid barge navigation. Image credit: NOAA/National Operational Hydrologic Remote Sensing Center.

Links
Adairsville Tornado Recap, Photos, and Video from Angela Fritz

A Wild Ride Weather-wise for the Eastern Half of the U.S. the past Four Days by wunderground’s weather historian, Christopher C. Burt.

Tornado Expert Sees “Staggering” Damage in Georgia

Have a great Groundhog’s Day and Super Sunday, everyone!

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/article.html

Overview of the 2012 Hurricane Season fr/Jeff Masters

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The bizarrely active hurricane season of 2012 draws to a close
Published: 4:50 PM GMT on November 30, 2012
The long and highly destructive hurricane season of 2012 has finally drawn to a close. The hurricane season of 2012 will long be remembered for spawning Hurricane Sandy–a freakish storm that was the largest, most powerful, and second most destructive Atlantic hurricane on record. But this year’s hurricane season had a number of unique attributes, making it one of the most bizarre seasons I’ve witnessed. Despite featuring a remarkable nineteen named storms–tied for the third highest total since record keeping began in 1851–this year’s hurricane season had just one major hurricane. That storm was Hurricane Michael, which stayed at Category 3 strength for a scant six hours. This is the least number of major hurricanes in a season since the El Niño year of 1997, which had only Category 3 Hurricane Erika. There were no Category 4 or 5 hurricanes in 2012, for just the 3rd time since the active hurricane period we are in began in 1995. The only two other years since 1995 without a Category 4 or stronger hurricane were the El Niño years of 2006 and 1997. Both of those seasons had around half the number of named storms of 2012–nine in 2006, and eight in 1997. The relative lack of strong storms in 2012 helped keep the Accumulated Cyclone Energy (ACE) down to 128, about 30% above average.


Figure 1. Hurricane Sandy at 10:10 am EDT October 28, 2012. Image credit: NASA/GSFC.

A near-average year for number of tropical cyclones hitting the U.S.
Since the active hurricane period we’ve been in began in 1995, the U.S. has averaged getting hit by 4 named storms per year, with an average of 1.7 of these being hurricanes, and 0.6 being major Category 3 and stronger hurricanes. This year, we were hit by 3 named storms (Beryl, Debby, and Isaac). One of these was a hurricane (Isaac). Sandy didn’t count as a hurricane strike on the U.S., since it transitioned to an extratropical cyclone a few hours before landfall. No major hurricanes hit the U.S., making 2012 the 7th consecutive year without a major hurricane strike. The only other time we’ve had a streak that long occurred between 1861 – 1868, during the decade of the Civil War.


Figure 2. Vertical instability over the tropical Atlantic in 2004 – 2012 (blue line) compared to average (black line.) The instability is plotted in °C, as a difference in temperature from near the surface to the upper atmosphere (note that the same scale is not used in all the plots, making the black climatological line appear different, when it is really the same for each plot.) Thunderstorms grow much more readily when vertical instability is high. Instability was near average during the August – October peak of hurricane season in 2004 – 2009, but was much lower than average during the hurricane seasons of 2010 – 2012. There was an unusual amount of dry, sinking air in the tropical Atlantic during 2010 – 2012, and the resulting low atmospheric instability reduced the proportion of tropical storms that have intensified into hurricanes. Vertical instability from 2004 – 2011 is taken from NOAA/RAMMB and for 2012 from NOAA/SSD.

Unusually stable air over the Tropical Atlantic in 2012
For the third consecutive hurricane season, 2012 featured an unusual amount of dry, sinking air over the tropical Atlantic and Caribbean Sea. Due to warmer-than-average sea surface temperatures and an active African Monsoon that generated plenty of African waves, a remarkably high number of tropical storms managed to form, but the unusually stable air in the hurricane genesis regions made it difficult for the storms to become strong. When we did see storms undergo significant intensification, it tended to occur outside of the tropics, north of 25°N, where there was not as much dry, sinking air (Sandy’s intensification as it approached landfall in Cuba was an exception to this rule.) If we look at the last nine hurricane seasons (Figure 2), we can see that the hurricane seasons of 2010, 2011, and 2012 all featured similar levels of highly stable air over the tropical Atlantic. This is in marked contrast to what occurred the previous six years. The past three seasons all featured a near-record number of named storms (nineteen each year), but an unusually low ratio of strong hurricanes. Steering patterns the past three years also acted to keep most of the storms out to sea. Is this strange pattern something we’ll see more of, due to climate change? Or is it mostly due to natural cycles in hurricane activity? I don’t have any answers at this point, but the past three hurricane seasons have definitely been highly unusual in a historical context. I expect the steering currents to shift and bring more landfalling hurricanes to the U.S. at some point this decade, though.


Figure 3. Sea water floods the Ground Zero construction site at the World Trade Center, Monday, Oct. 29, 2012, in New York City. Image credit: AP.

Most notable events of the Hurricane Season of 2012
Hurricane Sandy was truly astounding in its size and power. At its peak size, twenty hours before landfall, Sandy had tropical storm-force winds that covered an area nearly one-fifth the area of the contiguous United States. Since detailed records of hurricane size began in 1988, only one tropical storm (Olga of 2001) has had a larger area of tropical storm-force winds, and no hurricanes has. Sandy’s area of ocean with twelve-foot seas peaked at 1.4 million square miles–nearly one-half the area of the contiguous United States, or 1% of Earth’s total ocean area. Most incredibly, ten hours before landfall (9:30 am EDT October 30), the total energy of Sandy’s winds of tropical storm-force and higher peaked at 329 terajoules–the highest value for any Atlantic hurricane since at least 1969. This is 2.7 times higher than Katrina’s peak energy, and is equivalent to five Hiroshima-sized atomic bombs. At landfall, Sandy’s tropical storm-force winds spanned 943 miles of the the U.S. coast. No hurricane on record has been wider; the previous record holder was Hurricane Igor of 2010, which was 863 miles in diameter. Sandy’s huge size prompted high wind warnings to be posted from Chicago to Eastern Maine, and from Michigan’s Upper Peninsula to Florida’s Lake Okeechobee–an area home to 120 million people. Sandy’s winds simultaneously caused damage to buildings on the shores of Lake Michigan at Indiana Dunes National Lake Shore, and toppled power lines in Nova Scotia, Canada–locations 1200 miles apart!


Figure 4. Hurricane Isaac lit up by moonlight as it spins towards the city of New Orleans, LA, on August 26, 2012. The Suomi National Polar-orbiting Partnership (NPP) satellite captured these images with its Visible Infrared Imaging Radiometer Suite (VIIRS). The “day-night band” of VIIRS detects light in a range of wavelengths from green to near-infrared and uses light intensification to enable the detection of dim signals. Image Credit: NASA/NOAA, Earth Observatory.

Hurricane Isaac hit Louisiana as a Category 1 hurricane with 80 mph winds on August 28, but the storm’s massive wind field brought a storm surge characteristic of a Category 2 hurricane to the coast. A storm surge of 11.1 feet was measured at Shell Beach, LA and higher surges were reported in portions of Louisiana. Fortunately, the new $14.5 billion upgrade to the New Orleans levee system kept the city dry. Isaac killed 9 people in the U.S., and 29 in the Caribbean.

Hurricane Ernesto hit Mexico’s Yucatan Peninsula as a Category 1 hurricane with 85 mph winds on August 7. The storm killed 12 and did at least $250 million in damage.

Tropical Storm Debby formed on June 23, the earliest formation date on record for the season’s 4th storm. The previous record was Dennis, on July 5, 2005. Debby killed seven and did over $300 million in damage, but helped relieve drought conditions over Northern Florida and Southern Georgia.

Tropical Storm Beryl, which made landfall on May 28 near Jacksonville Beach, FL with 70 mph winds, was the strongest tropical storm to make landfall in the U.S. prior to June 1. Beryl killed two but did minimal damage.

Nadine lasted for 21.75 days as a named storm, the 5th longest-lasting tropical storm in the Atlantic basin.

It was the 3rd year in a row with 19 named storms.

No named storms existed during the month of July and November, but we still managed big numbers.

Only 7 seasons have had more hurricanes than 2012.

The season had two named storm before the official June 1 start of hurricane season, only the 3rd time that has occurred.

Eight named storms formed in August, which tied 2004 for the most to form in that month.

Typhoon Bopha a threat to the Philippines
In the Western Pacific, where typhoon season commonly brings several storms in December, we have impressive Typhoon Bopha. Bopha is expected to head west-northwest and intensify over the weekend, potentially arriving in the Philippines on Tuesday as a powerful Category 3 typhoon. Bopha formed at an unusually low latitude for a tropical cyclone–near 4°N. Storms forming that close to the Equator don’t get much help from the Earth’s spin to get spinning, and it is rare to see a tropical cyclone forming southwards of 5°N.

The Colorado State University hurricane forecast team, led by Phil Klotzbach and Bill Gray, has a more in-depth summary of the 2012 hurricane season.

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/article.html

Winter Storm Athena Heading for East Coast

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First Hurricane Sandy, now Winter Storm Athena for the Eastern U.S.
Published: 2:57 PM GMT on November 07, 2012

Winter Storm Warnings are up for Southwest New Jersey, Northern Delaware, and Southeast Pennsylvania, including Philadelphia, PA, where Winter Storm Athena is expected to drop 3 – 5″ of snow today through Thursday morning. Slushy accumulations of up to 1″ are likely in Baltimore, and non-accumulating snow will fall as far south as Washington, DC. Athena, the season’s first Nor’easter and first winter storm to get a name under The Weather Channel’s new naming system, is spreading rain and high winds into Southern New Jersey and Eastern Long Island, NY this morning. Winds at buoy 44025, about 40 miles offshore from the coast of Central New Jersey, reached 40 mph, gusting to 49 mph, with a significant wave height of 14′, at noon EST. Winds at Nantucket, MA have gusted as high as 54 mph this morning. Athena is building a storm surge that has already reached 2.2′ at Atlantic City and 1.8′ at New York City as of noon EST. A storm surge of 2 – 3.5′ is likely along the section of coast most heavily damaged by Sandy’s storm surge, and battering waves up to 20′ high will cause moderate beach erosion along much of the New Jersey and New York shoreline. The storm surge will cause minor to moderate flooding during this afternoon’s high tide cycle near 1 pm EST, and again at the next high tide, near 1 am EST Thursday morning. Fortunately, the high tides this week will be some of the lowest of the month, since we are midway between the new moon and full moon. Wind gusts from Athena will likely reach 50 mph along the coasts of New Jersey and Southern Long Island, NY, and could hit 60 mph on Cape Cod, Massachusetts. I expect that Athena’s winds, rains, and wet, heavy snows will cause up to 50,000 new power outages today. As of early Wednesday morning, 676,000 customers were still without power in the wake of Hurricane Sandy (down from a peak of 8.5 million customers.)


Figure 1. Winter Storm Athena as seen at 9:01 am EST November 7, 2012. Image credit: NOAA/GSFC.


Figure 2. Predicted storm surge at Sandy Hook, NJ, for Winter Storm Athena, from the experimental Extratropical Storm Surge model, run by NOAA’s Meteorological Development Laboratory. This model used winds from this morning’s 6Z (1 am EDT) run of the GFS model. The peak storm surge (yellowish-brown line) is predicted to be 3.4′, occurring Wednesday evening. High tide (green line) occurs near 1 pm Wednesday afternoon, resulting in a peak storm tide of approximately 7.2′ around 1 pm Wednesday (black line). For comparison, Sandy delivered a 8.6′ storm surge to Sandy Hook before their tide gauge failed, with the storm tide reaching 13.2′ above MLLW (Mean Lower Low Water.)

The decision to name Athena
The Weather Channel announced in October that they would begin naming winter storms this year, in an effort to aid in raising awareness and reduce the risks the public faces. One of the main criteria for naming a storm is its impact on populated areas; the meteorology of the storm may not get it named, if the storm doesn’t affect a populated area. If Hurricane Sandy had not devastated the region of coast being affected by today’s Winter Storm Athena, it may not have gotten a name. With so many people still under recovery efforts even well inland, the combination of heavy, wet snow and wind prompted the decision to name Athena. The models have been trending towards more cold air getting pulled into this system, so it is possible Athena could drop heavier snows than currently advertised. The National Weather Service will not be referring to today’s Nor’easter as “Athena”. They put out this internal directive: “The NWS does not use named winter storms in our products. Please refrain from using the term Athena in any of our products.”

Here are the peak wind gusts from Athena as of 11 am EST on Wednesday, November 7, 2012:

Jeff Masters

from:    http://www.wunderground.com/blog/JeffMasters/article.html

First Sandy, and Now, A Nor-easter

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A moderate-strength Nor’easter on Wednesday looking increasingly likely
Published: 7:38 PM GMT on November 03, 2012

Storm-weary U.S. residents pounded by Superstorm Sandy may have a new storm to contend with on Wednesday: an early-season Nor’easter is expected to impact the mid-Atlantic and New England with strong winds and heavy rain. Our two top models, the European (ECMWF) and GFS (run by the U.S. National Weather Service), are now in agreement on both the track and intensity of the storm. The storm will move off the coast of South Carolina/Georgia on Tuesday evening. Once over the warm waters off the coast, the low will intensify, spreading heavy rains of 2 – 3″ over coastal North Carolina on Tuesday night and Wednesday morning. The storm will accelerate to the north-northeast on Wednesday and pull in cold air from Canada, intensifying into a medium-strength Nor’easter with a central pressure of 984 mb by Wednesday evening. The European model, which did an exemplary job forecasting Hurricane Sandy, is slower, predicting the Nor’easter’s highest winds will begin affecting New Jersey on Wednesday night. The GFS model is about 12 hours faster, predicting the strongest winds will arrive on Wednesday morning. A 12-hour period of strong winds of 40 – 45 mph will likely affect the coast from Maryland to Massachusetts, accompanied by a swath of 2 – 3″ of rain. The heaviest rains will likely fall over Eastern Massachusetts and Rhode Island. The storm also has the potential to bring more than a foot of snow to mountain areas of New England. The storm is still four days away, and four-day forecasts of the path and intensity of Nor’easters usually have large errors. Nevertheless, residents and relief workers in the region hit by Sandy should anticipate the possibility of the arrival on Wednesday of a moderate-strength Nor’easter with heavy rain, accompanied by high winds capable of driving a 1 – 2 foot storm surge with battering waves. The surge and waves will potentially cause moderate to severe erosion on New Jersey coast, where Hurricane Sandy pulverized the protective beach dunes.


Figure 1. Predicted wind speed for Thursday morning, November 8, 2012, from the ECMWF model (left) and predicted wind speed for 2 pm EST on Wednesday, November 7, from the GFS model (right). Both models runs were done beginning at 12Z (8 am EDT) on November 3, 2012. Winds tropical storm-force (39+ mph) are predicted to extend from coastal Virginia to Massachusetts. The GFS model brings the Nor’easter to a point off the New Jersey coast about 12 hours faster than the ECMWF model.


Figure 2. Forecast track error for four of our top models used to predict Hurricane Sandy. The GFS model performed the best for 1 – 3 day forecasts, but the European (ECMWF) model far out-performed all models at longer-range 4 – 5 day forecasts. This may be due to the fact the model was able to successfully predict the timing of the arrival of a trough of low pressure over the Eastern U.S. that acted to steer Sandy to the north and then northwest. Image credit: Morris Bender, NOAA/GFDL.

Charities mobilize for Sandy
Sandy’s death toll of 109 in the U.S. makes it the 25th deadliest hurricane in U.S. history, and the 2nd deadliest since 1972, when Hurricane Agnes killed 122 in the Northeast U.S. The main owners of The Weather Channel have agreed to match donations of up to $1 million to the American Red Cross, with all donations to benefit people in the hard-hit areas of the U.S. To have your donation matched, please visit www.redcross.org/sandy, or text SANDY to 90999. I also recommend my favorite disaster relief charity, Portlight.org. They are focusing their response efforts exclusively on the post-Sandy needs of people with disabilities.Check out the Portlight blog to see what they’re up to. Sandy’s greatest devastation occurred in Haiti, where rains of up to 20 inches in 24 hours unleashed rampaging flood waters that killed at least 54, left 200,000 homeless, wiped out thousand of acres of crops, and killed massive numbers of livestock. For impoverished families in Haiti still struggling to recover from the earthquake in 2010 and Hurricane Isaac in August, Sandy was devastating. These crops are the very essence of rural Haitian’s livelihoods, and there are fears widespread starvation will result. A disaster relief charity in Haiti that I’ve contributed to for many years, The Lambi Fund of Haiti, is seeking donations to help farmers purchase local seeds so that they can replant their crops in the wake of this latest terrible Haitian catastrophe.

I’ll have an update Monday, unless there’s some major change in the model forecasts for the coming Nor’easter.

from:    http://www.wunderground.com/blog/JeffMasters/article.html